* Start of basic scrollbar drawing. This will be improved. Only Outliner shows these for now, as although the Timeline should show them, the old files didn't have them turned on.
* Tidied up the view-panning operator
- Fixed naming convention
- Added user-adjustable properties (deltax, deltay in screenspace)
* Added ctrl-scrollwheel (horizontal) and shift-scrollwheel (vertical) scroll operators. These use the view-panning code too.
Unfortunately, I haven't been able to figure out why the WHEELMOUSEDOWN events don't seem to be triggering the operators!
* Moved View2D data from space-data to ARegion (aka regions). This has been done because drawing occurs in regions not areas anymore. The View2D struct is currently stored in the ARegion struct (not as pointer), given that most of the regions in use will be 2D anyway (only the 3d-view's "window" region is the exception).
Added version patch code for outliner and timeline only for now. Headers are also likely to need this.
* Added separate keymap for View2D operators. All regions that use View2D will need this added. This includes headers too.
* Pan view operator (ED_View2D_OT_view_pan), currently works for Outliner and Timeline. Use MMB-drag as before.
- It currently doesn't exposed any parameters for redo (via RNA-ID-Props), but only uses some customdata. Suggestions on what these parameters could be are welcomed.
- I've yet to implement the necessary axis-locking features for this panning (which is required in Timeline for example to prevent vertical panning, which moves the markers out of view).
